The Southwold Archaeological & Natural History Society was set up principally to own the museum and to support it - financially (through subscriptions and fundraising), practically (by supplying the voluntary manpower and management expertise to run the museum and its associated library) and academically (through carrying out research and publishing the results).

In 2005 the Society was renamed 'The Southwold Museum & Historical Society', a registered charity whose primary purpose and function remain much as originally envisaged. It is curated, staffed and run entirely by volunteers drawn from the Society's membership which now exceeds 400. No charge is made for admission to the museum and all running costs are met by voluntary donations from visitors and by funds raised from the activities of the Society.

However, today those activities extend well beyond the museum itself. The Society is one of the most vibrant and active organisations in the area and runs a busy schedule of lectures, site visits, history- and natural history-related holidays and social events.